Process and apparatus for modifying plant extracts

ABSTRACT

Phytonutrients or other active materials can be extracted from plant material using a particular process which requires extracting juice from the plant material, followed by breaking open the plant cells to release the phytonutrients by subjecting the juice to high shear conditions, followed by concentrating the juice using a membrane which is preferably a nanofiltration membrane, and collecting the concentrated extract which can then be spray dried info a powder and used as a nutritional supplement, or which can be further extracted using supercritical carbon dioxide to provide an even more concentrated product. The process is designed to maintain a high levels of phytonutrients in the active condition and to reduce plant and equipment costs especially in the use of supercritical carbon dioxide.

FIELD OF THE INVENTION

The present invention is directed to a process that enables concentratedphytonutrients to be obtained from plant material, and a product made bythe process. The present invention is also directed to a method thatenables concentrated phytonutrients to be obtained in a cheaper manner.The present invention is also directed to a general process that enablesconcentrated plant extracts to be obtained.

BACKGROUND ART

Eating a balanced diet is essential for disease prevention, and tomaximise the benefits of a balanced diet, quantity and variety in thefruits and vegetables eaten is important. Fruits and vegetables containdifferent combinations of vitamins and minerals and other compoundscalled phytonutrients. Research is now providing evidence that healthbenefits of fruits and vegetables are also due these phytonutrients.

Plant extracts are gaining increasing demand for their therapeuticvalue. These compounds are also referred to as phytochemicals orphytonutrients. Phytonutrients can include nutritional substances infoods which act as important biological response modifiers. Examples arecarotenoids, the red-orange pigments that give fruits and a vegetablestheir distinctive colour. Many phytochemicals are anti-oxidants thatprotect the body against the damaging effect of oxygen free radicals.Many phytochemicals are converted by the body to vitamin A, which isused in the immune system as well as to prevent blindness.

Scientists are recognizing that a great many factors in foods contributeto their ability to act as modifiers of biological function. The use ofspecific whole foods and their concentrates, along with the traditionalvitamin and mineral factors, provides a much more powerful influence onnormalizing biological function and functional health than thetraditional diet of processed foods with the addition of a simplevitamin/mineral supplement with antioxidants.

There is a large range of plants that contain phytonutrients. Theseinclude a wide range of fruits, vegetables, spices, herbs and also otherplants that are not usually consumed in their natural state such asbarley grass, alfalfa, algae and medicinal herbs. Examples includegrapes, pineapples, oranges, blueberries, apples, cranberry, papaya,aloe vera, acerola, tomato, carrot, beetroot, broccoli, spinach, chilli,ginger, alfalfa, beetroot, olives, green tea, panax ginseng, lecithin(soy derived), inulin, and ginkgo biloba. Commercial fruit concentratesalso contain phytonutrients and these concentrates can contain redgrape, pineapple, orange, blueberry, apple, cranberry, papaya, aloevera, and acerola.

Phytonutrients are also found in many grass products which include wheatgrass, barley grass, alfalfa grass and spirulina.

However, the level of phytochemicals in plants is not large and a greatquantity of plant material must be consumed to benefit from thetherapeutic properties of the phytochemicals or other beneficialcompounds present in the plants.

For this reason it is known to extract the “actives” such as thephytochemicals and other beneficial components from plant material toprovide a concentrate.

It is very important that high quality plant extracts for medicinal andnutritional use are produced and which have a high level of thetherapeutically active compounds.

A well known process for producing herbal extracts andphytopharmaceuticals involves harvesting of the herbal plants, dryingthe plants, and then extracting active components from the plants with asolvent. The dried plants are ground to a fine chaff and placed intocolumns. A solvent percolates through the bed of dried plants in thecolumn, is collected and the solvent is removed to provide theconcentrate.

The use of dried herbs or dried plants as a starting point inpreparation of a concentrate has some disadvantages. The maindisadvantage is that the plant deteriorates during the drying process,and this results in a reduction of “actives” that can be removed, andalso allows the concentrate to contain deteriorated actives that can bea source of contamination in the final concentrate and that can bedifficult to remove from the concentrate. It is found that as soon asthe fresh plant is cut, the high moisture level allows the immediatemultiplication of microbes, bacteria and fungi. The enzyme systems inthese microbes start breaking down the phytochemicals in the plantswhich can also include the pharmacologically active compounds. Thenatural enzyme systems in the plants themselves also begin the processof breaking down the plant phytochemicals as soon as the plants areharvested.

Another disadvantage is that the cost of drying can be substantial interms of labour and capital equipment. Most plants in their fresh stateconsist of approximately 90% moisture, so there is a large amount ofwater to be removed. Drying costs can be reduced by windrowing in thefields for a few days, but this can only increase the level of breakdownin the plant material and leaves the plants exposed to contamination.

Another disadvantage is that dried herbs or other plants may be storedfor a relatively long period of time (up to six months) prior to beingsold to processes for solvent extraction. This can contribute further tothe decomposition of pharmacologically active compounds in the plantmaterial.

Surveys of retail dried herbal products purchased from health shops showa wide range of therapeutic activities, and this is probably caused bythe conventional drying process. It is not desirable to have a product(e.g. dried herbs) having varying levels of activities as this can leadto dosage errors.

The conventional method of concentrating the dried plant material bysolvent extraction also suffers from disadvantages. Solvent extractionis carried out on ground dried plant material (e.g. dried and groundherbs) by allowing the particular solvent to percolate through a bed ofground plant material in a column. Due to the low bulk density of theplant material in the column, large volumes of solvents are required toextract the actives (e.g. phytochemicals). Also there is a highproportion of inert plant fibre that has no therapeutic value that takesup room in the column. At the end of the extraction this bulky herbresidue must be compressed to recover solvent, so there can beconsiderable losses of expensive solvents.

Another problem with conventional solvent extraction in the use ofground dry plants in a column and using solvent, is the limited yield.The plant material cannot be ground too fine, as the solvent will notpercolate through the bed (usually under gravity). Because the plantmaterial must be relatively coarse (fine chaff), the penetration of thesolvent is limited so yields of active are low and larger volumes ofsolvent are required to improve extraction. However, if the plantmaterial is not finely ground, the plant cells will not break open torelease the phytonutrients from the plant cells. Therefore, this currentextraction method requires a balance between grinding sufficiently to atleast partially open the plant cells but not grinding so finely that itbecomes almost impossible to pass solvents through a column containingthe ground plant material. This process is therefore inherentlyinefficient.

Another problem with large packed columns is channelling, where someplant material is under-extracted and other parts over-extractedresulting in low yields and use of high amounts of solvents.

Obviously, it is desirable to extract the plant material using non toxicsolvents. However many active components in the plant material have lowsolubility in non toxic solvents (e.g. water or a water/ethanolmixture). For this reason rather toxic solvents such as N-hexane,acetone, methanol and methylene chloride are used to extract therapeuticactives. There is always concern about the amount of toxic solventresidue that remains after distilling the solvent from the extract.These organic solvents are toxic, many are highly flammable and pose avery high fire risk and can also be quite expensive.

It is also known to extract actives from plant material usingsupercritical carbon dioxide as the solvent. This process involvesfilling a column with ground dried plant material and pumpingsupercritical liquid carbon dioxide though the column at very highpressure (200-400 Bar).

The low bulk density of the ground herbs used to pack the columnrequires that the dimensions for the column be large to accommodatecommercial production i.e. 200-300 litres. However the vessel mustwithstand 200-400 Bar so the vessel has to be engineered very strong andmade of stainless steel, due to the corrosive nature of low pH of liquidcarbon dioxide, which makes for a very high capital cost. The largedimension of the vessel also requires large amounts of carbon dioxide,so these two factors make for a very expensive extraction process. Alsolarger diameter columns reduce the efficiency of plug flow through. Thelarge volume of carbon dioxide used requires that the must be recycledaround the system in a closed loop which means further high capital costof refrigeration equipment and a bulk liquid carbon dioxide tank. Afurther drawback in current process is that volatile componentsextracted from the plants can be retained in the carbon dioxide when itevaporates in the separation tank. This means that these extractedvolatile materials build up in the carbon dioxide in the recirculationloop. This also contaminates the carbon dioxide for use in extractionfrom the next plant species used in the extractor.

In the current form used supercritical carbon dioxide extraction is avery expensive process so it can only be applied to very high valueplant extracts. A reference article (Fine Chemicals 1998) compares thepay back rate in months for various extraction systems. Hexane  9 monthsSteam  37 months Super critical carbon dioxide 540 months

This high cost makes the extraction of only very high value activecomponents a commercial proposition.

However, supercritical carbon dioxide extraction is otherwise a verygood method to concentrate the actives in plant material, so there wouldbe a great advantage if the cost of supercritical carbon dioxideextraction could be reduced both in operating and capital cost.

There would also be a great advantage if it were possible to provide aplant concentrate that did not require a long drying process prior toextraction with a solvent.

There would also be a great advantage if it were possible to product adried flowable solid product (e.g a powder) from the concentrate andthat has a good level of actives.

There would also be a great advantage if it were possible to provide aprocess to prepare a concentrate and which reduced the need for toxicorganic solvents and which could lower the volume of solvent required.

It will be clearly understood that, if a prior art publication isreferred to herein, this reference does not constitute an admission thatthe publication forms part of the common general knowledge in the art inAustralia or in any other country.

OBJECT OF THE INVENTION

It is an object of the invention to provide a process which provides aconcentrate extracted from plant material and which may overcome atleast some of the above-mentioned disadvantages or provide a commercialor useful choice.

In one form, the invention resides in a method to provide a concentrateobtained from plant material, the method comprising at least partiallyextracting juice from the plant material, subjecting at least some ofthe extracted juice to shear conditions to at least partially open plantcellular material, and removing at least some of the water to provide aconcentrate.

It can be seen that this method does not require the use of plantmaterial that has been dried for long periods of time and therefore thestarting material is not appreciably deteriorated compared to plantmaterial that has been dried for a long time. Of course, the inventioncan use dried plant material if desired but need not be limited to theuse of dried plant material. For instance, it may be possible toreconstitute dried plant material by mixing with water.

The plant material will typically comprise plant material that containsphytonutrients or other desirable active material. Suitable plantmaterial will be as described above. The plant material may compriseleaf material, stem material, tubers, root material the entire plant,part of the plant and the like. However, if it is known that thephytonutrients are overwhelmingly present in a certain part of the plant(e.g. in the tuber with respect to carrots) then it is preferred thatonly this part of the plant is used in order to avoid inefficiencies.

The plant material can be initially collected by any suitable means orby any harvesting means. This may include manual harvesting, automatedharvesting etc. It is preferred that the plant material is processed asquickly as possible after being harvested in order to preventdeterioration of the plant material that has been described above.Typically, the delay between harvesting and processing should be only afew hours and ideally should be less than two hours. However, it may bepossible to subject the harvested plant material to low temperatures inorder to prevent or to reduce deterioration and thereby enabling thedelay to be somewhat larger. For instance, it may be necessary to callthe harvested plant material to between 3°-10°. This can be done at anysuitable means including cold water, cold air etc.

Suitably, the harvested plant material is subject to a sterilising stepprior to extraction of the juice. The sterilising step may be conductedusing a bactericide. A suitable bactericide may comprise ozone. However,the invention should not be limited only to the use of this particularbactericide.

The liquid, or juice can be extracted from the plant material by anyconventional means. This may comprise the use of pressure to extractplant juice from the plant. However, no particular limitation needs tobe placed on the invention by the method by which the liquid is removedfrom the plant material. The plant material will typically be chopped,crushed etc to assist in removal of the plant juice. It is preferredthat as much juice as possible is removed from the plant material. Thus,it is preferred that between 20%-99% of the juice is removed from theplant material.

This crushing and extraction process may release some of thephytonutrients, but many phytonutrients will still be locked away inintact cell structures in the juice.

It is preferred that the juice is screened to remove plant fibres, andother nonsoluble material. The screen may comprise a relatively coarsescreen to remove only the relatively cause plant fibres and nonsolublematerial.

The juice, or at least part of the juice is then treated to conditionsof high shear. There are commercial machines that will subject the juiceto conditions of high shear. One commercial machine is known as theSILVERSON machine. In this particular machine, the juice is subject tointense hydraulic shear. The shear conditions will open up more of theplant cell structure is to release phytonutrients which would beotherwise locked away. The above commercial machine has been identifiedas an example of a machine that can provide conditions of high shear,but no particular limitation is meant thereby, and invention is not tobe limited only to this type of machine to provide the high shearconditions to the extracted liquid/juice.

The treated juice (that is the juice that has been treated to the shearconditions) is then concentrated to form a concentrate. It is preferredthat the concentration is carried out using a semipermeable membraneprocess as this does not require the use of large amounts of heat. Aparticularly preferred membrane separation process is nanofiltrationwhich can remove up to 80% of the water. An advantage of using ananofiltration membrane is that the membrane as well as removing thewater will also remove salts such as potassium chloride.

It is preferred that the concentrated material is dried into a solidflowable material (such as a powder). This can be done using aconventional drying process which requires the use of heat, but theamount of heat required may be considerably less due to the initialconcentration of the juice.

Prior to, or after drying the concentrated material, it is preferredthat the concentrated material is subjected to an extraction step. Theextraction step may comprise solvent extraction. The solvent maycomprise supercritical carbon dioxide which has been described above.

The extracted material from the solvent extraction step will typicallybe high in phytonutrients, and this material can then be dried into aflowable material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1. Illustrates a general flowchart

DETAILED DESCRIPTION

General Process Description

Stage 1

The invention relates to a process for extracting active nutraceuticaland phytopharmaceutical phytochemicals from plants using the freshplants, or dried plants reconstituted with water where no fresh plant isavailable.

The plants are harvested and brought to the processing facility toprovide a short “harvest to extraction time” i.e. less than two hours.If the weather is warm or there is a transport time of greater than twohours, the harvested plants are cooled to 3-10° C. in the field. At thefactory the harvested plant material is held in a cold room.

The plant material is first washed and sterilised using a bactericide inthe washing water.

The plant material is spun dry and ground in a milling unit that feedsto an extraction press where the plant juice is extracted underpressure. The fibre from the press can be blended with water and morejuice extracted.

After screening through a strainer to remove the coarse fibre, thejuice, which is not a true solution but rather a fine suspension ofextracted plant, material is submitted to high shear mixing to releasethe contents of the chloroplast and plant cells.

This solution is then pumped through a membrane cartridge, preferablynanofiltration, which has the capacity to remove 80% of the water. Themembrane rejects molecules above approximately 300 daltons and has lowrejection of monovalent salts such as potassium and chloride, which arethe main salts in plant extracts.

Another advantage of using nanofiltration membranes for concentration isthat that the low rejection of the nanofiltration membrane for saltsreduces the increase in osmotic pressure of the solution as it isconcentrated. This allows the membranes to remove significant quantitiesof water an reach concentration factors of better than 5 on thetherapeutic active components that are of most interest.

If further concentration is required this can be achieved at lowtemperature using vacuum evaporation. Concentration by membrane is muchlower cost than vacuum evaporation.

A dry extract can then be produced by low temperature spray drying.Because only a small amount of the original water is left to be removedin the spray drying stage (in the order of 5%) only a small spray drieris required. Fine atomisation of the feed into the spray drying processgives evaporation in a fraction of a second and the dried particles arecooled due to the evaporative cooling effect. Operating withdehumidified drying air can reduce the operating temperature.

This powdered product can be sold in a powdered form or formulated intodose forms such as capsules, tablets, gels and the like or incorporatedinto topical formulations.

Where a more refined extract is required the retentate fromnanofiltration can be processed using microfiltration. The permeate froma microfilter with a pore size of 0.2 microns will produce a sterileproduct.

Further refinement and concentration of therapeutic active componentscan be achieved by using the spray dried powder from Stage 1 as the feedstock for a variety of STAGE 2 solvent extraction processes.

Stage 2—Solvent Extraction

In a further embodiment the spray dried powder from Stage 1 can beextracted using super critical fluid extraction with carbon dioxide oralternatively extraction with a range of organic solvents.

The SCF-CO2 process is a liquid/solid extraction process with carbondioxide under high pressure acting as the solvent. Due to the largereduction in the volume of plant material achieved by using the spraydried powder from STAGE 1 as the feed stock instead of the originaldried plant material the size of the high pressure vessel for supercritical extraction can be reduced by 60 to 80%.

In a further embodiment the spray dried powder can be extracted by thestandard array of organic hydrocarbon solvents. However, the quantity ofsolvents used is substantially reduced and the capital expenditure oncolumn is much lower. The organic hydrocarbon solvents can be distilledoff to produce an oleo resin. The organic hydrocarbon solvent can alsobe removed by using solvent resistant nanofiltration membrane process.In this process the solvent extract is pumped through a nanofiltrationmembrane cartridge at high pressure in the range of 10 to 30 bar.

Stage 3

In a further embodiment the oleo resin from STAGE 2 can be furtherextracted using a liquid/liquid super critical fluid extraction columnusing super critical carbon dioxide as the solvent.

In a further embodiment, the SCF, CO2 extract can-be used innutraceutical products, phytopharmaceutical and cosmeceuticalcompositions suitable for use by humans.

In a further embodiment of the invention the SCF, CO2 extract from STAGE2 can be further refined to isolate particular phytochemicals by the useof solvent extraction using a range of organic solvents from thegroup—hexane, methanol, acetone, ethanol and methylene chloride.

In a further embodiment the organic solvent extract from stage 2 can befurther refined to phytochemicals using columns for adsorption, ionexchange or chromatographic separation.

In a further embodiment the product from the stage 3 Liquid/liquid SCFCO2 process can be refined by the use of adsorbents, ion exchange,chromatographic separation. In a further embodiment the CO2 separationvessel from the liquid/liquid SCF CO2 column can be preceded by a packedcolumn containing an adsorbent, ion exchange resin or chromatographicresin.

In a further embodiment the SCF CO2 from STAGE 2 can be further refinedusing SCF Chromatography. In this process SCF CO2 is used as the carriersolvent in the chromatographic column. The chromatographic columnoperates at high pressure and the column is packed with the usualchromatographic packing such as C18.

GENERAL EXAMPLES

The extraction process is in two stages:

Stage 1—Aqueous extraction from the fresh plant through to a spray driedpowder.

Stage 2 —Solvent extraction of the spray dried powder from stage 1 toproduce an extract with very high concentrations of Phytochemicals

This stage 2 solvent extraction can either use SCF CO2 which is thepreferred embodiment or and solvent.

According to the invention, the plants for extraction are harvestedeither by machine or hand and are transported immediately to theprocessing facility. If the time from harvest to processing is going tobe greater than two hours, then the harvested plants are field cooledrapidly to between 3° C. and 10° C. by circulating chilled water overthem. Another known process for rapid cooling of plant material is avacuum cooling chamber. Commercial units are available that can coolproduce to 2° C. within 30 minutes.

Plant material can be held in cold stores at the processing facility ifthere is a delay in processing.

The extraction process starts with the washing of the plant materialusing high pressure water sprays followed by a holding bath withdissolved ozone. The ozone bath is maintained at 2-6 mg per litre ofdissolved ozone, with the optimal level being 4 mg of ozone per litre.

The plant material is spun dry to remove excess water and passes to amilling unit. This unit can be a commercial hammer mill or cuttergrinder. It is considered that a skilled person will understand the typeof milling unit that can be used to crush the plant material.

The milled plant material passes to a press to extract the juice. Thereis quite a range of commercial presses that can perform the task, suchas a roller mill, screw press, belt press and air bag press. It isconsidered that a skilled person will understand the type of presses orother devices that can be used to extract juice from the plant material.

The extracted juice passes over a strainer to remove larger plantparticles that have been extracted with the juice. The screen opening isbetween one and four millimetres, with the preferred opening being twomillimetres. It is considered that a skilled person will understand thetype of screens or other types of filters that can be used to removelarge plant particles that have been extracted with the juice.

To improve extraction the fibre left from the first press can be mixedwith water and then passed through the press again to yield a dilutedjuice, which can be combined with the first pressings.

The filtered juice is then subject to high shear. A number of commercialunits are available for this process. The high shear can be imparted byan homogeniser or Silverson mixer (Trade Mark). An homogeniser forcesthe liquid stream through very fine openings to create high shear. ASilverson mixer stirs the liquid stream and draws it past impellerrotating at high speed with narrow clearance between the outside cage.It is considered that a skilled person will be able to understand thetype of machine or device that can be used to imparted a high shear onthe filtered juice.

The extracted juice is not a true solution but includes a suspension offine plant particles such aggregates of plant cells and chloroplasts. Itappears that the high shear at least partially breaks down thechloroplast and plant cells and releases their contents into solutionthereby increasing the availability of active compounds.

This treated juice is filtered using a strainer with an opening of 50 to500 microns with a preferred opening of 100 microns. A commercial unitmost suited for this is a rotating stainless steel wedge bar strainerwith self cleaning back flush. The back flush can be high pressure wateror steam. It is considered that a skilled person will understand thetype of strainer that can be used to filter the treated juice.

The filtered juice then passes to the membrane separation plant. Themembrane plant is fitted with a commercial spiral wound nanofiltrationmembrane as suplied by Osmonics Corp U.S.A. The pore size of themembrane is selected depending on the size of the molecules to berejected by the membrane. In the preferred embodiment a nanofiltrationmembrane has a rejection or from 150 to 500 daltons . Suitablecommercial membrane cartridges are spiral wound cartridges. The poresize of these membranes is 5 to 20 angstroms with a preferred pore sizeof 10 angstroms. The membranes operate at high crossflow and atransmembrane pressure of 10 to 40 Bar with a preferred operatingpressure of 25 to 35 Bar.

The membrane has a low rejection for water and monovalent salts such aspotassium and chloride. These salts pass through the membrane with thewater as the permeate. Ninety-eight percent of the organic moleculesabove 300 daltons are retained by the membrane and there is still a highrejection down to 200 daltons.

The majority of organic molecules above 200 daltons are the ones showingtherapeutic properties. These can include the following non limitingexamples:

Carotenoids Beta-carotene, Alpha-carotene, Lycopene, Lutein, Zeaxanthin

Flavonoids: Quercitin, Rutin, Anthocyanins, Catechins, Procyanidins,Coumarin

Phytoestrogens:

Isoflavones genistein, daidzein, glycitein, Coumestans, Lignans,Resveartrol

Glucosinulates:

sulforphane

Allylic compounds:

Diallyl sulphide

Terpenoids

Phenolic acids

Cholorophyll

Many of the organic molecules of pharmacological interest are 5 to 10times this size so there is almost 100% retention of the most desiredcomponents. Examples of these large molecules are flavanoids,isoflavones, polysaccharides, polyphenols, carotenes, and glycosides ofsmaller ring compounds.

This membrane separation stage can concentrate the liquid extract by afactor of four to six times. A solids level from 15% to 20% can beachieved in the membrane retentate.

This membrane concentrated extract can be spray dried at thisconcentration or concentrated further by vacuum evaporation to aconcentration of 30% to 40% solids depending on the viscosity of theconcentrate which can vary depending on the species of plant beingextracted. Commercial vacuum evaporators used for this type ofconcentration can be flash evaporators or an Alfalaval spinning conevacuum evaporator, which operate at low temperature and evaporate atapproximately 45° C. to 50° C. vapour temperature.

The concentrated extract is then dried to a powder using a lowtemperature spray drying technique. The commercial spray drier used forthis stage is a small tower spray drier using air atomisation. Airatomisation gives very fine particle size and rapid equilibrium. It isconsidered that a skilled person will understand the technique requiredto convert the concentrated extract into a flowable solid products suchas a powder.

The incoming air has been dehumidified so drying can take place at lowtemperature. Incoming air temperature is in the range of 100 to 200° C.The rapid evaporation of water from the very fine atomised particlescauses adiabatic cooling so that the product particles are not heatedand the enzyme systems and therapeutically active components in theseparticles retain all of their activity. With this technique even heatsensitive products can be dried.

This spray dried powder is the raw material for the stage 2 extractionprocess; however these powders can be marketed as a separate product intheir own right.

The dried powder can be marketed as a nutraceutical, herbal medicine ornutritional supplement. The product is suitable to be formulated intothe following dose forms-powder, capsules and tablets. An advantage withthis product is that the membrane separation process removes most of thepotassium chloride. Potassium chloride is deliquescent (absorbs moisturefrom the atmosphere) and it has been observed with powder nutritionalsupplements from other manufacturers that have not been through ourmembrane process, the powder in retail packs soon goes lumpy after thebottle has been opened due to absorption of moisture from theatmosphere. Also moisture absorption can be a problem as microbes cangrow when sufficient moist has been absorbed.

These manufacturers add quantities of starch a filler to try and mop upthis absorbed moisture to keep their product free flowing. This additionof a filler is undesirable because larger doses are required because ofdilution of the actives.

Where higher levels of actives are required in a botanical extract orphytopharmaceutical or phytochemical the dried powder product can beused as the feedstock for more sophisticated downstream extractiontechniques.

Second Stage Extraction

The next stage of extraction that can be used is a batch typeliquid/solid extraction using supercritical carbon dioxide as thesolvent.

Supercritical fluid extraction operates by pumping supercritical CO2through the solid ground plant to be extracted at very high pressure ina column. The compounds extracted by the supercritical CO2 depend on thepressure applied to the column. More volatile compounds such asessential oils are extracted at low pressures. Other compounds such ascarotenoids are extracted using higher pressures. That is, thelipophylic solvent properties of the supercritical carbon dioxide can beincreased by increasing the pressure in the column. The higher thepressure the more lipophilic the solvent properties of the carbondioxide become. The critical point for carbon dioxide is 31° C. and 73ATM. SCF extraction operates at moderate temperatures 35 to 400° C.Operating pressures for essential oils can be down to 100 ATM and highermolecular weight compounds such as carotenoids around 250 to 300 ATM.The CO2 extract passes through a reducing value and into a separationtank where CO2 evaporates to a gas leaving the extracted therapeuticactives behind in the separation tank. Pressure reduction is usuallydown to 40 to 60 ATM.

By preparing a spray dried powder from the fresh plant the volume ofsolids to be extracted is substantially reduced and can be in the orderof five times smaller than what would be required if dried whole plantswere used in the column.

These extraction columns are fabricated from stainless steel and operateat very high pressures; 200 bar to 500 bar, so large columns are veryexpensive to build. A five fold reduction in the size of a column cangive very substantial reduction in capital costs for an SCF(supercritical fluid) plant. Large columns and bed depths result inpoorer distribution of solvent and hence give lower yield.

One of the main operating costs for SCF is the cost of liquid carbondioxide solvent. The much smaller column in this invention usessubstantially less carbon dioxide.

Another major capital cost is a CO2 recovery system. This may not berequired if low volumes of CO2 are used in the smaller SCF column.

In a further embodiment the powder from stage one used as feed to theSCF, CO2 column can be pelletised into fine extruded rod a about 1 mmdiameter.

In a further embodiment the spray dried powder from stage one can have asmall amount of excipient added such as methyl cellulose. The excipientadded can be any of a large number of inert polymers that will not bedissolved by the supercritical carbon dioxide. This inert frame worksupports the column packing while the carbon dioxide dissolves theactive therapeutic actives out of the matrix. This mixture can becompressed into small tablets or formed into beadlets using a coatingdevice. The SCF CO2 extractor can then have the bed constructed as aradial flow bed with reduced path length and high capacity for the smallcolumn.

In another embodiment of the invention the powder from the spray driercan be extracted by non polar organic solvents. The choice of solventvaries depending on the species of plant being extracted or the type ofpharmacological active being extracted. The following is the range oforganic solvents used for this type of extraction: -n-hexane, acetone,methanol and methylene chloride.

In existing processes the organic solvent extraction takes place on theoriginal ground dry herb. The ground plant is filled into columns andthe organic solvent percolates through the bed.

In this embodiment the spray dried powder already contains highconcentrations of the actives. The organic solvent extraction can takeplace in a much smaller vessel and substantially less organic solvent isrequired.

Because the powder is very fine the extraction can take place in astirred tank reactor and a very high recovery of therapeutic active canbe achieved. The solvent extract is filtered from the residue and thesolvent removed by vacuum distillation.

Because in this process much less organic solvent is used therefore thedistillation equipment can be much smaller and operating costs are lowerdue to the substantial reduction in expensive organic solvents used. Theorganic solvents are toxic and highly flammable so the smallerquantities used make for a much safer commercial process.

The product from many of these organic solvent extractions result in anoleo resin after the solvent has been evaporated under vacuum. Oleoresins can be used in a range of products and have a high level ofactives.

Further extraction of the oleo resin can be carried out by usingliquid/liquid supercritical fluid extraction in a continuous columnusing supercritical CO2. The oleo resin is pumped into the top of thecolumn through a pressure reducing valve to a separation tank where theCO2 evaporates away leaving the refined product with higher level ofactives in the product.

Analyte (waste) passes out at the base of the column. The productsextracted from the oleo resin depend on the operating pressure of theSCF column.

Higher pressures are required to dissolve the higher molecule weightproducts required. Volatile products can be SCF extracted by CO2 ataround 200 bar high molecular weight products can be extracted at 250 to300 Bar.

A preferred embodiment of the present invention can include thefollowing steps:

Short harvest to extraction time for fresh plant,

Sterilising the plants by washing with ozone saturated water,

Pressing out the fresh juice,

Breaking open the plant cells and choroplasts in the juice with highshear mixing,

Fine straining of the juice,

Concentrating using nanofiltration membranes to concentration factor offive,

Removal of monovalent ions and water in the nanofiltration membranepermeate,

Optional further concentration by vacuum evaporation,

Low temperature spray drying of the concentrate to form a powder,

Agglomerating the powder with a high molecular excipient such as methylcellulose,

Further extracting the spray dried solids by liquid/solid supercriticalfluid extraction with CO2 to produce a refined product with a high levelof actives,

Operating the liquid/solid SCF CO2 a sequential range of pressures toproduce various fractions of extract containing different therapeuticactives,

Alternatively adding a modifier to the CO2 such as ethanol,

Alternatively, in another embodiment, extracting the spray dried solidswith a range of organic solvents to produce oleo resins with a highlevel of actives,

Downstream extraction of the oleo resins using liquid/liquid SCF withCO2 in a continuous column to produce highly refined products with highlevel of actives.

The aqueous extraction of the fresh plant along with the concentrationand fractionation by nanofiltration membrane can be carried out withhigh volumes plant material with safety and low cost. The spray drierrequired is only small since most of the water has been removed bymembrane at low cost.

The large reduction on solids from fresh plant to the spray dried powderallows for a dramatic reduction in the size of the down streamextraction units required, namely:

liquid/solid SCF extraction

organic solvent extraction

In the process where aqueous extraction of the fresh plant is followedby:

high shear mixing

membrane processing

spray drying

agglomeration with a polymer

liquid/solid SCF extraction with CO2

We have a process where in the preferred embodiment no undesirableorganic solvents have been used in the extraction process. The organicsolvents are toxic and highly flammable and require special facilities.There is always concern about the level of residue left in the productfrom organic solvents. International regulations are being introduced tolimit the amount of organic solvent residue.

If the plant source is from organic certified crops then this processwould be the only extraction process of this type that could becertified as organic. Ie. The cleanest, greenest process for extractionof nutraceuticals and phytopharmaceuticals.

The resulting products have the higher levels of therapeutic activesthan any other process because there is no losses when the plants aredried. Very high yields are obtained by using high sheer to open up thechloroplasts and plant cells.

Specific Example 1 Chilli

A crop of cayenne chilli was harvested and delivered to the processingfacility within one hour.

100 kg of chilli was washed with high pressure water and then submergedin a wash bath containing water at 20 degrees celsius with dissolvedozone at a concentration of 5 mg per litre. The chilli was drained andthen milled in a stainless steel hammer mill.

The milled material passed into a screw press and the juice wasextracted. Large solids 1-2 mm were removed in a wedge bar strainer witha clearance of I The juice was pumped to a 100 litre tank and blendedwith high sheer using a Silverson mixer. The blended juice was thenpassed through a fine wedge bar strainer with a clearance of 100microns.

The juice was then pumped at high pressure (2500 Kpa) through ananofiltration spiral wound membrane cartridge. The membrane was aspiral wound nanofiltration cartridge from Osmonics U.S.A. with anominal pore size of 10 angstroms. (10 000 angstroms=1 microns)

The operating temperature was 25 degrees Celsius. A concentration factorof 5 was achieved. The permeate from the membrane process containedmainly water and monovalent ions -chloride, sodium and potassium. Theconcentrate was spray dried in a small tower spray drier using airatomisation. The drying air was dehumidified by refrigeration. The yieldof spray dried powder from the original 100 kg of chilli fruits was 6kg.

The spray dried powder was agglomerated by blending with methylcellulose and drying in a fluid bed drier. The agglomerated matrix wasloaded into a 10 litre batch operated liquid/solid supercritical fluidCO2 extractor. Supercritical liquid Carbon Dioxide was passed throughthe column at 35 degrees Celsius and 220 bar pressure.

The liquid carbon dioxide extract passed through a reduction valve andinto a separation tank at 50 bar. The CO2 extract was warmed to 35 C andthe CO2 evaporated leaving a residue with a high level of capsaisin themain active phytopharmaceutical

Specific Example 2 Solvent Extraction of Chilli

The spray dried powder from Example 1 was extracted by solventextraction in a small stirred tank reactor. The solvent used wasacetone.

The acetone was removed from the extract by vacuum evaporation toproduce an oleo resin. This oleo resin was extracted in a small stirredtank reactor. The solvent used in this stage was ethanol. The ethanolwas removed from the extract by vacuum distillation to yield a second,more refined, oleo resin with high levels of capsaicin.

This oleo resin can be used at a 10% concentration in pressure spraysfor personal protection, riot control and disarming criminals. Theoleoresin can also be used as concentrated chilli flavour in foods.

The oleo resin from this stage can be further refined by using aliquid/liquid supercritical fluid extraction using CO2.

The oleo resin was pumped into near the top of the small stainless steelSCF column. Supercritical carbon dioxide was pumped in near the bottomof the column and passed counter current to the oleo resin flow.

The extracted product passed out of the top of the column and after thepressure reducing valve the CO2 evaporated to leave a high purityproduct residue of capsaicin. To meet United States Pharmacopoeiastandards, the product must contain 70% of capsaisinoids. The columnoperated at 35 degrees Celsius and 200 bar.

Specific Example 3 Red Clover

A crop of red clover was harvested and rapidly cooled in field using avacuum cooling chamber. The cooled red clover was taken to the factoryand held in cold storage at −2 degrees C.

100 kg of red clover was washed with high pressure water and then passedthrough a bath of water with dissolved ozone at a concentration of 5 mgper litre.

The red clover was drained and passed through a stainless steel hammermill with a 10 mm screen. The milled material passed into a screw pressand the juice was extracted. The extracted juice passed through astrainer to remove particles above 2 mm. The juice then passed through ahigh sheer Silverson mixer to release the contents of cells andchloroplasts.

This product them passed through a fine 100 micron wedgebar screen. Thisfiltered juice was then concentrated and modified using nanofiltrationmembrane which removed water and monovalent ions. Chloride, sodium,potassium. The juice was further concentrated to 30% solids in a vacuumevaporator. This concentrate was then dried in a tower spray drier usingair atomisation. The resulting spray dried powder had a moisture contentof below 5%.

This powder product could be marketed in a powder form as a rich sourceof isoflavones.

The powder was agglomerated with methylcellulose in a fluid bed drierand fed into the vessel of a supercritical extractor. Supercriticalcarbon dioxide was pumped through the vessel and then passes through areducing valve and into the separation tank.

A product separated out in the separation tank that was very rich in theisoflavones—genistein, daidzein, formonontein and biochanin.

Specific Example 3 Red Grapes

A fresh supply of red grapes was purchased and washed in a commercialTipax washer manufactured by Tripax Engineering, Victoria Australia. Theproduct is drawn down deep into the tank by means of a vortex created byangled underwater jets. The washed grapes spill over to a dewateringvibrator and up a conveyor into the hammermill and then into a screwpress.

Red juice is extracted solids are retained by a 0.7 mm screen.

The juice is subjected to high sheer in a Silverson mixer and thenpassed through a 100 micron strainer to a nanofiltration membrane plantfitter with a nanofiltration spiral wound cartridge. The membrane isoperated with a transmembrane pressure of 2,500 KPa. A clear permeatepassed from the membrane and a dark red retentate was produced rich ingrape polyphenols.

A small quantity of malto dextrin was blended with the red juice and theconcentrate was spray dried using a Niro spray drier. A rich red brownpowder was produced. contiaing a rich source of grape polyphenols.

Specific Example 4 Solvent of the Grapes

Red grapes contain a range of poly phenols including anthocyanins andresvertarol. Red grape powder was charged into the extraction column ofa supercritical carbon dioxide extractor. C02 supply from cylinder wasfed to a high pressure pump and passed into the high pressure extractioncolumn.

Optimised Supercritical extraction conditions. Sample 30 gramsExtraction vessel 50 ml Pressure 420 bar Flow rate gas 4 l/minTemperature 60 C.

An oleo resin was collected in the separation vessel after a pressurereducing valve down to 60 bar.

Specific Example 5 Carrots

100 kg of fresh washed carrots were purchased direct from the markets.

The surface of the carrots were washed by a high pressure water sprayand then in a tank of ozone water. The residence time in the ozone watertank was five minutes and the ozone level was maintained at 2 mg perlitre.

The carrots were dewatered on a vibrating conveyor befor being elevatedinto a stainless steel hammer mill.

The hammermill was a commercial unit with a capacity of 1,000 Kg per hrand powered by a 4 kW electric motor. The rotational speed of the swinghammers was 2,800 rpm.

The carrot mulch passed through the screen into a stainless steel screwpress which extracted a bright orange juice. The waste fibre had almostno residual colour.

Weighing of carrot feed and fibre showed a 50% yield of carrot juice.The juice passed to a Silverson L4RT high sheer mixer fitted with asquare hole disintegrating head. The variable speed control was set at arotational speed of 6,000 rpm as shown on the tachometer. High sheer wasmaintained for three minutes per batch at a temperature of 23 C.

The juice was then passed through a rotating wedge bar strainer with 100micron openings. The strained juice passed to a membrane separationplant using a Nanofiltration spiral wound cartridge from Osmonics U.S.A.Membrane pore size one nanometre. The juice was concentrated by pumpingat high cross flow through the membrane cartridge at 2,500 kPa pressure.

A clear permeate flowed from the membrane and the retentate turned fromorange to brown as the B carotne became more concentrated.

The juice concentrate was dried using a Niro spray drier. An addition of55 on solids of maltodextrin was added to the juice before spray drying.The drier operated with a 4 kW electric heater with an inlet airtemperature of 200 C and and exit air temperature of 75 C. Feed waspumped into the atomiser nozzle using a peristaltic pump. The finecarrot powder was separated in a cyclone into the collecting chamber.

Specific Example 6 Solvent Extraction of Carrot Extract

The carrot powder from Example 5 was filled into an extraction vessel ona supercritical carbon dioxide extractor.

Carbon dioxide was released from a cylinder to a high pressure pumpwhich also had a precooler. The pressure in the extraction cylinder wasprogressively ramped up to 250 bar and the flow rate set. The operatingtemperature was 40 C. At this temperature the Carbon dioxide was in asupercritical state and acted as a lipophilic solvent. The solvent CO2passes through the column of carrot powder and then through the reducingvalve until the pressure dropped to 60 bar. At this temperature the oleoresin was released into the separating vessel. The oleo resin was a richorange brown showing a high level of B carotene.

Specific Example 7 A Grass

A crop of Alfalfa was harvested using a forage harvester and theharvested crop was brought directly to the processing facility.

The Alfalfa was washed with high pressure water spray and transferred toa conveyor belt feeding a hammer mill. The leaf was milled through a 5mm screen and fed directly into a belt press.

The belt press was a commercial unit with a metre wide belt. At a feedrate of one tonne per hour the belt press delivered a very bright greenjuice at a rate of 500 Kg per hour.

The juice was subjected to high sheer using a Silverson high sheermixer. A temperature of 25° C. was maintained while the stirrer operatedwith a batch time of three minutes. The Silverson mixer used was a BXmodel with a 0.75 kW motor and a speed of rotation of 3,000 rpm.

The unit was fitted with the standard disintegrator head.

The juice was passed through a 180 micron screen to the 200 litre feedtank of the membrane separation plant.

The custom built membrane plant used a 100 mm diameter spiral woundnanofiltration cartridge supplied by Desal, California U.S.A. Nominalpore size one nanometer. Typical rejection of 95% of molecules over 300daltons. Permeate Membrane Retentate Feed Permeate Volume Pressure Timemin Temp Cel Brix Conductivity Conductivity Collected 2,500 KPa 0 20 5.55.1 mS 3.49 mS 20 litres 2,500 10 24 6.4 4.14 20 l 2,500 20 27 7.5 4.1620 l 2,500 30 35 11.5 4.54 20 l 2,500 40 40 15.0 Final 9.1 mS 5.36 20 l

The rich green juice was concentrated by membrane by a factor of 5:1.

Examination of the membrane permeate showed that it was water clear sothat no green components passed through the membrane.

The conductivity of the nanofiltration permeate rose from 3.39 milisiemens to 5.36 mili siemens demonstrating the large quantity of mainlymonovalent ions that were removed in the permeate.

Dry substance analysis was performed on the feed juice and the finalmembrane retentate.

Feed solids 8.3%

Final retentate concentrate solids=17.1%

Solids were determined by oven drying for 2 hrs at 95 C.

Microscopic examination of the concentrate showed fine green particlesand a very bright green solution compared with the clear permeate.

Feed conductivity 5.1 mS Final concentrate conductivity 9.1 mS alsodemonstrating a moderate rise in minerals despite the 5:concentrationfactor.

Throughout the specification and the claims (if present), unless thecontext requires otherwise, the term “comprise”, or variations such as“comprises” or “comprising”, will be understood to apply the inclusionof the stated integer or group of integers but not the exclusion of anyother integer or group of integers.

Throughout the specification and claims (if present), unless the contextrequires otherwise, the term “substantially” or “about” will beunderstood to not be limited to the value for the range qualified by theterms.

It should be appreciated that various other changes and modificationscan be made to any embodiment described without departing from thespirit and scope of the invention.

1. A method to provide a concentrate obtained from plant material, themethod comprising at least partially extracting juice from the plantmaterial, subjecting at least some of the extracted juice to shearconditions to at least partially open plant cellular material, andremoving at least some of the water to provide a concentrate.
 2. Themethod as claimed in claim 1, wherein the concentrate is dried to asolid flowable material.
 3. The method as claimed in claim 1, whereinthe concentrate is extracted with a solvent to produce an extractedmaterial.
 4. The method as claimed in claim 2, wherein the flowablematerial is extracted with a solvent to produce an extracted material.5. The method as claimed in claim 3, wherein the solvent issupercritical carbon dioxide.
 6. The method as claimed in claim 4,wherein the solvent is supercritical carbon dioxide.
 7. The method asclaimed in claim 4, wherein a filler is added prior to solventextraction.
 8. The method as claimed in claim 1, wherein the water isremoved using a semipermeable membrane.
 9. The method as claimed inclaim 8, wherein the semipermeable membrane is a nanofiltrationmembrane.
 10. The method as claimed in claim 1, wherein the concentratecontains phytonutrients.
 11. The method as claimed in claim 1, whereinthe plant material is selected from the group consisting of fruits,vegetables, spices, herbs, grasses.
 12. A solid flowable material madeby the method of claim 9.